Is 70% good enough?

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 - Mary Tierney

Not exactly. A recent study, the largest of its kind that tracked more than 1,000 children, found a 70 percent success rate using balloon aortic valvuloplasty (BAV) to treat isolated congenital aortic stenosis (AS).

Like nearly every medical study published, this one in JACC: Cardiovascular Interventions owns up to its faults and lays out goals for future research and success. The authors called BAV “safe and effective” in treating patients with congenital AS, but they also note the study included data only up to hospital discharge so adverse outcomes could have been underreported. The study also relied on operators to grade aortic insufficiency.

But to interested onlookers, “an overall success rate of 70 percent leaves much room for improvement,” wrote interventional cardiologists Ziyad M. Hijazi, MD, of Weill Cornell Medicine in New York, and Damien Kenney, MD, of Our Lady’s Children’s Hospital in Dublin, in an accompanying editorial. Longer-term studies and a standardized approach, they said, could reduce adverse events for patients with congenital AS.

Although popular since the mid-1980s, BAV has yet to be proven superior to surgery. As the doctors said: “Ultimately, we believe a randomized trial with surgical valvotomy including longer-term follow-up is warranted to ensure we do not spend another 30 years in the dark as to the optimal approach for this troublesome disease. Our surgical colleagues are very keen on participating in such a trial. We owe it to our patients and their families to answer this question once and for all: Is BAV as good, better or inferior to surgical aortic valvotomy?”

We are all better in teams working together.

Sure, we will continue to strive for greater than 70 percent success, but we’re clearly helping a lot of sick kids. The study by Brian A. Boe, MD, with Nationwide Children’s Hospital in Columbus, Ohio, and colleagues looked at 1,026 patients with those younger than one month the most prevalent age group with 27 percent, followed by infants one to 11 months old at 25 percent, and adolescents aged 11 to 17 years with 18.6 percent. About 10 percent of patients had critical AS, while 89 percent had noncritical AS.

Adverse events, when they occurred, were more likely in those patients undergoing BAV for critical AS. Unsuccessful procedures were often attributed to significant aortic insufficiency (AI) as determined by the operator (12.1 percent). A significant aortic valve gradient (greater than 35 millimeters of mercury) occurred in 11.4 percent of procedures, and a combination of the two occurred in 6.5 percent of overall procedures. Patients with severe AS had a 30 percent incidence of adverse events compared to 14.1 percent in the noncritical AS group.

The study found six factors were associated with unsuccessful BAV in noncritical AS patients, namely previous cardiac catheterization, mixed valve disease, baseline aortic valve gradient greater than 60 mm Hg, baseline AI greater than mild, presence of a trainee and multiple balloon inflations.

“Four of these six factors are patient-related and support a growing body of research linking BAV outcomes with the intrinsic characteristics of the aortic valve,” Boe and colleagues noted.

We have learned from this study and move on. Medicine never settles for good enough. Sooner rather than later, we hope another study will work to decide the most successful method to help kids.